[Gaffer]

They also used to use the ‘bent-fin’ technique on the rounds. Gives the round a nonstandard parabolic trajectory that makes source detection hard.

[Chainmail]

"They also used to use the ‘bent-fin’ technique on the rounds."

Never heard of that one! Bent fins would make the round wobble and maybe even whistle and less likely to hit what you're aiming at - but the trajectory would still be parabolic.

Been in the mortar business for decades - never hear 'O that one..